Tag Archives: maths

Floating and Sinking; What is the best material for a life jacket?

We had great fun this week in Senior Infants in room 2. We wanted to find a good material to use in life jackets so we started by investigating different materials to see if they would float or sink when placed in water. Before we tested the materials, as a class we chose eleven different materials to test. We predicted what we thought would happen to each material. There were 19 people in the class at the time and we counted how many people thought that the object would float or sink and recorded the results in the table below. pic

We tested the materials by placing the object in a basin of water and watched to see if it floated or sank. We recorded the results in a table.

pic2From this experiment we learned that if an object is lighter than water it will float and if an object is heavier than water it will sink.

Having identified different materials that floated, we investigated what material would be good to use for to make life jacket. We discussed how to stay afloat in the water and what things help us to float in water. We made six people using plasticine and when we placed them in water each of them sank to the bottom. We chose 6 different materials (felt material, bubble wrap, inflated balloon, cotton wool, polystyrene and cork) and compared their weights and classified them as heavy or light. Each of the plasticine people was attached to a material. They were placed in the water and we observed which of the materials worked best to keep the person afloat. We made a list of the materials in order of which would work best for a life jacket.

1. Polystyrene

2. Balloon

3. Cork

4. Bubblewrap

5. Felt material

6. Cotton wool

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Chemical Energy and Capacity

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We had great fun creating lava lamps in 2nd class.

Now we know that chemical energy is energy released during a chemical reaction.

We found out that oil and water do not mix. Water is heavier than oil.

For our lava lamps we used effervescent tables (these are tablets that dissolve in water) called Alka Seltzer. These tablets have two chemicals in them called citric acid and bread soda.

If you follow our experiment you can make your own cool lava lamp.

Here is our experiment

Title: To design and make a lava lamp and learn about chemical energy.

Equipment: Effervescent tablets, food colouring, oil, water, plastic bottle

Prediction: I predicted that the oil and water would not mix and that the food colouring and oil would mix.


  1. Find out the capacity of the bottle by filling the bottle with water and empty water into measuring jug.
  2. Calculate a quarter of the capacity of the bottle and put this amount of water in the bottle.
  3. Now calculate two quarters of the capacity of bottle and add this amount of oil to the water
  4. Now add about 8 or 10 drops of food colouring to the bottle.
  5. Break the effervescent tablet (alka seltzer) into pieces and drop them into the bottle.
  6. Leave the bottle for an hour or so, observing it from time to time.
  7. Now add another bit of alka seltzer tablet and observe what happens.

We will update you with our results and conclusion next week!


We used our maths skills today to find out how much water and oil was needed in each bottle.

If you have a litre bottle = 1000ml you will need to fill it with a quarter of a litre of water which is 250ml and two quarters of a litre of oil which is 500ml.

If you have a 500ml bottle you will need to fill it with a quarter of 500ml of water which is 125ml and two quarters of 500ml of oil which is 250ml.

Check out our capacity post here.

Paper Helicopters

In room 10 we decided to experiment with energy and forces. We each made two paper helicopters using a simple template.

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    What we need-

  • Paper Helicopter Template.
  • Scissors.
  • Paper Clips.
  • Ruler.

With our paper helicopters made we then measured the length of the blades, we wanted to have one helicopter with long blades and one helicopter with short blades. we discovered that our long blade helicopters flew longer and further than our short blade helicopters, this is because of the force and energy pushing up against the blades.

We also experimented dropping the helicopters from different heights- We noticed that the higher up from the ground that we released the helicopter, the further it flew and the longer it took to reach the ground.

Finally, we tried to change another variable and we added one or two paper clips onto the stem of our helicopter. This changed the weight of our helicopters and the results showed that this made the helicopters fly even faster.

Heart Rate Before and After Exercise

Today in our class we monitored some children’s heart rates before exercise and then we monitored it after exercise. We found out that your heart rate increases after you complete exercise. These are the results

Name Before exercise After exercise
Anais 106bpm 178bpm to 160bpm
Ronan 86bpm 178bpm to 99bpm
Brandon 93bpm 170bpm to 108bpm
Molly 95bpm 128bpm to 95bpm

Click on the following links to see the graphs

Brandon’s Heart Rate Before & After Exercise

Molly’s Heart Rate Before & After Exercise

Ronan’s Heart Rate Before & After Exercise

Anais’ Heart Rate Before & After Exercise

6th Class Reaction Testing.

We decided to test reactions for our latest Science project. How fast our reaction speeds are and if there are differences with age, gender etc?

We marked a ruler using  a template between 0.01  up to 0.25 seconds.

One person held the ruler on top while the person being tested had the 0.00 mark between their thumb and forefinger.

The person holding  the ruler drops and the the person being tested has to try to catch it.

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We recorded the scores as a time in seconds

Class Average

The very first part was to test everybody and get a class average.

We found that  our class average was 0.22sec

class average


We also looked to see how many were faster or slower than the class average we found


56% were Faster than average

36% were slower than average

8% were exactly average

Gender differences/Gender Averages

For the boys (15 of them) their average speed was 0.24sec.

40% were faster than average

53% were slower than average

7% were exactly average

Boys avg

For the girls (10 of them) the average speed was 0.20 sec

30% were faster than average

50% were slower than average

20%  were exactly average.

Girls average


Reaction Times across the school.

We looked at reaction times for boys and girls from age 5 to 13 across the school.
From the data we have collected we have found out that as you get older your reaction times get faster. In our graph it shows that the eleven year olds had a faster time then the twelve year olds. We collected information from the ages of of 4 years olds to 12 year olds. We tested them five times each then found the average times for each age group.



‘Frog Jumps’ in Junior Infants

We have been learning about frogs in Junior Infants. We investigated if we could jump the same length as a frog. We read that a frog can jump up to 20 times the length of its own body. We estimated that the length of a frog’s body was 2 inches. We measured a frog’s jump as 40 inches.
Our equipment:
• A metre stick
• Camera
• Book: ‘Tadpoles and Frogs’
• Ourselves
Our prediction:
We predicted that we would be able to jump the same length as a frog.
Our Method:
We placed our metre stick on the yard and we measured 40 Inches. We each had a turn to jump and measure the length of our jumps.
We took photographs as proof of our result.
Our result:
We could jump the same length as a frog based on our estimation!

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Growing seeds in Junior Infants

We did an experiment, over one week, to see if seeds need water and light to grow and survive.
Our Equipment
• Three cups
• Cotton wool
• Water
• Cress seeds
• Camera
Our Prediction
We think that the seeds without water and the seeds without light will not grow. We think that the seeds with water and sunlight will grow.
Our Method
We put two cups of cress seeds on the windowsill, we watered one of them each day and did not water the other.
We hid other seeds away from sunlight in the corner of our book shelf.
We watered the control plant and the plant on the bookshelf every day.
We took photographs as the experiment progressed.
The Result
The seeds without water did not grow.
The seeds without sunlight did not grow.
Control: The plant with water and sunlight grew in one week.

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Heart Rate (bpm)

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Today in second class we all monitored our heart rate with the heart rate monitor.

Our hearts are pumping at a regular rate. This pumping can be felt by placing fingers across the pulse point at the wrist or the neck, and the rate can be counted. An adult’s heart rate is around 70 beats per minute, and a child’s is a bit higher. Heart rate increases with exercise so that more of the oxygen carried in the blood can reach the muscles. The fitter you are, the quicker your heart rate returns to normal.

BPM stands for beats per minute.

Click on the link and you can see a graph showing Jakub’s Heart Rate

This link shows Jakub and Ava’s Heart Rate. Ava’s heart rate was around 92 bpm and Jakub’s was around 73bpm.

We hope to do some exercise tomorrow and monitor our heart rates after. They should be higher than they were today!

Khan Academy – Up and running

We are well and truly up and running now with Khan Academy with both fourth classes motoring ahead in getting points and badges for their classes. We always knew that they were better at maths than the fifth and sixth class pupils! Catch up if ye can!

To keep up to date with Khan Academy, check out the Khan Academy Blog