Super Cold Bag with Science Visitors

We had special visitors today come and see how we 'do science'. These visitors are teachers who are on a Science Leadership course with the Royal Society. They are from all over New Zealand.

The experiment we did today had a fantastic chemical reaction - one that none of us guessed would happen. The photos tell a bit of the story.


Try this at home - here's what to do:-

Materials:

 · Citric Acid

 · Baking Soda

· Tap Water

· Zip lock bag (15cm x 10cm)

· Measuring cup

 · Plastic teaspoon

Perform this experiment over a kitchen sink or outside. There is a small chance the zip lock bag will burst making a wet mess!

What to do:-

Put one level teaspoon of citric acid in a zip lock bag

 Put one teaspoon of baking soda in the same zip lock bag. And shake the bag gently to mix the two chemicals.

Fill up the measuring cup with cold tap water (about 30ml).

Carefully place the water in the bag and zip the bag shut.

 Tip the cup over in the sealed bag and watch! Not only does the bag blow up, it also becomes super cold! So don’t forget to feel its temperature.

What’s happening and why: Mixing citric acid, baking soda and water together causes a chemical reaction. The new chemical that is made is carbon dioxide gas. This gas fills the bag and causes it to blow up. You’ll also notice the bag drops in temperature as part of the chemical reaction.

Energy Transfer

We've been looking into Energy Transfer with large and small balls. We placed the small ball on top of the larger one and dropped them. They fell to the ground and all the energy that was going into the bounce of the large ball got transferred into the smaller ball, springing it way up in the air. The large ball hardly bounced at all. This sort of thing can happen when we bounce with a friend on the trampoline sometimes too!

Egg-citing Discovery!

The 'science spot' in Discovery had an Easter theme with eggs - raw eggs!

What we needed was:
A large glass of water
A plastic plate
A cardboard tube (1/3 of a  glad wrap roll but a toilet paper tube would work just as well!)
A raw egg

What we did:
1. Place the plate on top of the glass of water
2. Sit the cardboard tube on top of the plate, lined up directly over the glass
3. Rest the raw egg sideways on the tube
4. Knock the plate out of the way and see what happens!

 

A special thanks to our 'eggs-pert' Damon for the demonstration

What was going on:?:

This is very like the table cloth trick where you pull out the cloth and everything stays on the table. Only this has a higher success rate! 

The plate needed a rim to catch the edge of the tube. The egg is just sitting - not moving. As the support is moved, gravity makes it drop and it lands in the water. (One of Newton's laws of motion) 

Have a 'crack' at this at home- outside!

Happy Easter everyone!

Scents and Stinks!

In Discovery time today we tried to identify different smells and similar smells. We practised wafting smells carefully. Sorting different smells wasn't as easy as some thought! Great fun though!