Science Project on “Retaining Freshness”, Project Experiment Topics on Human Beings, Animals Plants for Class 8, 9, 10 and 12 Students.
Retaining Freshness
Materials Required:
- Four brands of plastic food-wrap
- A ruler
- Masking tape
- Spring-type clothespins
- Scissors
- A table
- Pencil and paper
We have many ways to preserve food and to keep it fresh. After dinner, when there are leftovers, people often wrap them up in a plastic wrap or put the food in bowls and cover them with a wrap.
If the air is to be kept out of the plastic wrap, so that the food remains fresh, care must be taken to make sure that the wrap clings to the food or the top of the bowl. Is there a difference in the “clinging effect” in the brands of plastic food-wrap? Do some wraps cling better than others? Do a test to understand it.
Cut two pieces of a brand of plastic food wrap. Each piece should measure one foot (30 cm) long by one foot wide. Use masking tape to attach one piece of the wrap to the edge of the table, so that it hangs down.
Take the second piece of wrap and press it onto the bottom of the hanging piece, overlapping the pieces by two inches (5 cm).
Hang a spring-type clothespin on the bottom piece of the wrap. Keep hanging more of these, until the bottom piece of the wrap falls off.
Write down the number of clothespins the wrap held, before it lost its grip.
Do this again for other brands of plastic wrap and also include a store or generic (without a name) brand.
which food-wrap tested had the most “clinging effect”? Which one had the least?
Compare the prices of the food-wrap you tested. Does the wrap that clings best, also cost the most?
Which brands of wrap are the easiest and the hardest to get off the roll?
What about bowl cling? Put some coins or small stones into a bowl and cover it with a plastic wrap.
Does it hold when you turn the bowl upside down? Watch out! Does the kind of bowl make a difference, that is, if it is made of plastic or glass? Does it matter, if the outside of the bowl is wet or dry?
Do all brands of plastic wrap do a good job of keeping foods fresh? Cut five slices of apple.
Wrap four of them in different brands of wrap. Mark them, so that you are aware which wrap is where. Leave one slice of apple unwrapped.
Put them all in the refrigerator. Look at the slices every day. What do the apple slices look like, at the end of a week?